Physicists make laser beams visible in vacuum

A beam of light can only be seen when it hits matter particles and is scattered or reflected by them. In a vacuum, however, it is invisible. Physicists have now developed a method that allows laser beams to be visualized even under these conditions. The method makes it easier to perform the ultra-precise laser alignment required to manipulate individual atoms.

source https://www.sciencedaily.com/releases/2021/08/210825143048.htm